257 is a whole number, interger, and a rational number.
5x + y = -13.....multiply by -3
4x + 3y = -17
-----------------
-15x - 3y = 39 (result of multiplying by -3)
4x + 3y = -17
-----------------add
-11x = 22
x = -22/11
x = -2
5x + y = -13
5(-2) + y = -13
-10 + y = -13
y = -13 + 10
y = -3
solution (-2,-3)
$346/100=$3.46 =1% of $346. So, giving 10% discount we $3.46*90=$311.40
Again, $311.40/100=$3.114, providing, 10% discount we get $3.114*90=$280.26.
The net cost after the series discount is $280.26